Mono-substituted hydrocarbon fuel additives



United States Patent 3,523,769 MONO-SUBSTITUTED HYDROCARBON FUEL ADDITIVES James W. Tooke, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed July 25, 1966, Ser. No. 567,401

Int. Cl. C101 1/22 US. Cl. 44-72 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to combustion modifiers for fuels and to a method for improving the combustion characteristics of such fuels. In one aspect, there is provided an engine fuel composition comprising a combustible hydrocarbon or derivative thereof and a small amount of a compound chosen from certain compounds having two mono-substituted amine groups. In another aspect, a combustion modifying amount of one or more compounds chosen from certain compounds having two mono-substituted amine groups per molecule is added to a hydrocarbon spark ignition engine fuel to improve the combustion characteristics thereof. In yet another aspect, the performance of hydrocarbon fuels for spark ignition engines is substantially improved by effecting the ignition and combustion of said fuels in the presence of a combustion modifying amount of one or more compounds chosen from certain compounds having two mono-substituted amine groups per molecule.

Hydrocarbon fuels intended for application in relatively high compression internal combustion engines can be manufactured and refined to such an extent that they are of sufficient quality to provide the desired combustion characteristics Without the necessity of effecting such combustion in the presence of modifying agents. However, the refining techniques required to produce fuels of such high quality, of course, add appreciably to the cost of the fuel. In addition, the demand for even higher quality in such fuels is continually increasing and becoming even more critical with the introduction of higher compression engines. As a result, it has been a practice for some time to combine combustion improving additives with these hydrocarbon fuels to achieve the desired combustion characteristics without the necessity of producing a hydrocarbon mixture that will itself provide the desired results. These additives have met with varying degrees of commercial success due primarily to the differences in expense, performance characteristics and combustion product contaminant level. In particular, when hydrocarbon fuels containing lead and anti-knock or octane improving agents are burned in internal combustion engines, at least a portion of the additive is converted to a deposit of nonvolatile lead compounds which accumulate on the various parts of the engine which result is, of course, very undesirable. In addition, the additive combustion products that migrate from the engine and exhaust system are also non-volatile and, as a result, become dispersed in the atmosphere in the form of fine particles, thereby resulting in contamination of the atmosphere. We have found that through the use of the hydrocarbon fuel additive of this invention the desirable improvement in combustion characteristics can be achieved while substantially reducing the detrimental characteristics of the combustion products.

It is therefore an object of this invention to provide a novel fuel composition having improved combustion and octane properties. It is another object of this invention to provide a novel gasoline range hydrocarbon fuel composition for internal combustion engines. It is yet another object of this invention to provide a hydrocarbon engine fuel composition having therein a novel hydrocarbon fuel additive, which fuel composition has improved combustion characteristics and which produces combustion prodnets of substantially reduced detrimental contaminant level.

Other aspects, objects and the several advantages of this invention are apparent to one skilled in the art from a study of this disclosure, and the appended claims.

In accordance with this invention, the efliciency and quality of combustion of hydrocarbons is greatly improved by eflecting the combustion in the presence of a relatively small amount of compounds having the general formula carbon fuel at the operating temperatures of the spark ignition engines in which their use is intended.

The mono-substituted amines of this invention are suitable additives for essentially all combustible hydrocarbons. However, they are most advantageously employed to improve the combustion efiiciency of internal combustion engine fuels and particularly gasoline range hydrocarbons. Such fuels generally include gasolines, benzene, fuel oils, kerosene, or blends or mixtures there of. The improvement in combustion eificiency that results through the use of the composition of this invention is manifested by an improved anti-knock performance of the engine, by increased mileage obtained from the base fuel in a given engine, by the permissible use of leaner fuel-air mixtures, and by increased power output.

The improved fuel compositions of this invention comprise a hydrocarbon fuel of the type described usually having a boiling point within the range of from about to about 450 F. in combination with a combustion modifying amount of the mono-substituted amine additives of this invention. In the presently preferred embodiment of this invention, the additive concentration ranges up to about 10 percent although sufiicient improvement in com bustion characteristics can be achieved by maintaining the concentration of these additives within the range of from about 0.1 to about 5 weight percent.

Compounds illustrative of the inventive additives of this invention are as follows:

N,N'-dimethylethylenediamine N,N-diethylethylenediamine N,N'-diethylbutylenediamine N,N'-diethylhexylenediamine N,N-dimethylmethylenediamine N-benzyl-N-methylpentylenediamine N,N'-dimethyloctylenediamine N,N-dicyclohexylbutylenediamine N,N-diisopropylethylenediamine N,N'-dicyclohexylisobutylenediamine N,N'-dimethyl-Z-methylpentylenediamine N-methyl-N-isopropylhexylenediamine N-( 2,8,10-trimethyldodecyl N-pentadecylhexylenediamine N,N'-dipentadecylhexylenedamine N,N-di (hexyl-p-tolyl )hexylenediamine N,N'-dicyclododecylpentylenediamine.

These compounds have suitable solubility and volatility characteristic to permit their application as additives for hydrocarbon fuels.

The essential characteristic of the additives of this in vention is that the amino groups are mono-substituted and not di-substituted. This is for the reason that additives containing di-substituted amino groups appear to have a detrimental effect on the octane of the hydrocarbon fuel as illustrated in the following example.

EXAMPLE One liquid volume percent of each of certain diamines (based on the total volume of diamine and reference fuel) was blended with 80 octane number primary reference fuel and with 80 octane primary reference fuel containing 1.0 ml. tetraethyl lead per gallon of fuel. The blends so obtained were run in comparison to unblended 80 octane number primary reference fuel and 80 octane primary reference fuel containing 1.0 ml. tetraethyl lead per gallon of fuel respectively, in a standard knock test engine under standard conditions. The following results were obtained:

Octane number change in reference fuel Diamine compound No TEL 1.0 ml. TEL

Invention:

N,N-dimethylethylenediamine +2. +0. 6 N,N'-diethylethy1enediamine +1. 2 +1. 2 N,N-diethylbutylenediamine +0. 5 +0. 5 N ,N-diethylhexylenediamine +0. 2 +0. 2 Control:

N,N,N,N-tetramethylethylencdiamine l. 6 l.6 N,N-dirnethylcthylcncdiamine 0. 5 N,N-dimcthyltrimcthylcnediaminc. 0. 0 0. 7 N,N,N-trimethyltrimethylenediaminc 0. 3 0. 7 N ,N ,N ,N-tetran1ethyltrimetliyloncdiamine -1.0 1.2

This example clearly demonstrates the utility of this invention and the fact that the compounds of this invention produce the desired effect while closely related compounds are not effective. In fact, both N,N,N,N'-tetramethyl substituted diamines and N,N-dimethylenediamine caused a reduction in octane number.

Although the compounds included within the general formula are suitable as hydrocarbon fuel additives within the concept of the present invention, it is presently preferred that the additive compositions comprise akylene diamines wherein both amino groups are mono-methyl or ethyl-substituted and wherein the alkylene group has from about 2 to about 6 carbon atoms.

Reasonable modification and variation of the concept of this invention will be apparent to one skilled in the art in view of the foregoing disclosure and the appended claims to this invention, the essence of which is that there is provided an improved hydrocarbon engine fuel composition comprising a combustion modifying amount of a compound having the general formula I claim:

1. An engine fuel composition comprising primarily combustible hydrocarbon comprising a hydrocarbon distillate fuel and having therein a combustion modifying amount of at least 0.1 percent by weight of a compound having the general formula UNITED STATES PATENTS 2,021,088 11/1935 Pevere 44-72 2,305,673 12/ 1942 Chenicek 4472 2,305,674 12/ 1942 Chenicek 4472 2,305,676 12/1942 Chenicek 4472 2,324,118 7/1943 Sweeney 44-72 2,333,294 11/ 1943 Chenicek 4472 2,447,615 7/1948 Jones 4472 2,653,862 9/ 1953 Trimble et a1. 4472 2,758,916 8/1956 Mahan 44-72 2,891,850 6/1959 Cosgrove 4472 3,355,490 11/1967 Van Munster 4472 DANIEL E. WYMAN, Primary Examiner Y. H. SMITH, Assistant Examiner 

